// Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package pipe

import (
	"os"
	"os/exec"
	"syscall"
)

// addInheritedFile add a file that will be inherited by the new process.
// Note that the file must be marked as inheritable.
func addInheritedFile(cmd *exec.Cmd, file *os.File) uintptr {
	fd := file.Fd()
	if cmd.SysProcAttr == nil {
		cmd.SysProcAttr = &syscall.SysProcAttr{}
	}
	cmd.SysProcAttr.AdditionalInheritedHandles = append(cmd.SysProcAttr.AdditionalInheritedHandles, syscall.Handle(fd))
	return fd
}
